1. Technical Field
This device relates to spacer blocks for attachment of guard rails to support posts.
2. Description of the Prior Art
Guard rails are typically installed along highways as a roadway safety barrier system. The guard rails are usually formed as strips of material, typically extruded metal about 12 feet long and weighting about 90 pounds. A preferred embodiment comprises an elongated strip of metal, usually composed of galvanized steel, (typically about 12 gauge), aluminum, steel, fiber glass, or even synthetic materials. At least one configuration of a guard rail used includes a corrugation forming an undulating cross section in order to absorb energy upon receiving an impact from an out of control vehicle to prevent or at least control the direction of the vehicle prior to its leaving the roadway. Typically these beams are about 9 inches wide, have two crowns and are shaped substantially like the letter xe2x80x9cWxe2x80x9d. An alternate corrugated guard rail is known in the industry as a thrie beam which has three crowns and is about a third wider than the conventional two crown guard rail. Usually a plurality of guard rails will be linked together horizontally at their distal ends, either end to end, or overlapping, and be supported by a plurality of vertically oriented posts which are typically xe2x80x9cI-beamedxe2x80x9d shaped, round, or square posts which are driven into the ground spaced apart a selected distance from the edge of the road. Of course, posts are also fabricated from aluminum, wood, or other metals and could be formed from polymers or fiberglass materials. The posts are usually driven into the ground and typically will yield under a desired amount of pressure and move within the ground or bend in accordance with the deformation of the guard rail rather than break off at ground level, in order to assist the rail in dissipating force upon receiving a blow from a vehicle.
Typically a spacer block is disposed between the guard rail and the post to support the guard rail at a selected distance from the post to prevent an uncontrolled vehicle from hitting and entangling the posts. Thus, the spacer block keeps the automobile wheels from impacting the posts and initiating a roll of the vehicle. Moreover, the guard rail provides a continuous rail or track for guiding the vehicle providing at least some response time for the driver to regain control of the vehicle before leaving the roadway.
The most popular material spacer blocks are made out of is wood. Some of the problem with wood is it deteriorates over time, it is heavy, it can give installers splinters, it contracts and expands with season changes. Also, wood tends to leach out chemicals typically used for pressure treating which may be toxic to the environment. Conventional plastic blocks on the market today are typically wood block designs made out of plastic.
It typically requires two to three people to install a 12 foot section of guard railing to posts when using conventional spacer blocks, one to hold the guard rail and another to align and hold the spacer block in position with the post and a third person to insert bolts therethrough securing same.
The instant invention provides a spacer block having improved strength, reduced weight, and competitive cost. Furthermore, the spacer block of the present invention was designed with the assembly process in mind in order to enable a single individual to erect a guard rail safety barrier system on spacer blocks supported by posts.
The guard rail support attachment and positioning block or spacer block is used to space guard railing away from posts such as xe2x80x9cIxe2x80x9d beams which are driven into the ground.
The spacer block of the instant invention provides a design that is strong yet light, which makes it installation friendly, reduces the cost of manufacture, and permits one person to install a section of guardrail. In the past it might require two or three people to hold the rail and mount it to the spacer block and support post.
Plastic properties are different from wood and requires a design that takes advantage of the different properties. The present design is specific for plastic, (polyethylene, PVC, polypropylene polyethylene terphthalate, nylon), or plastic/rubber and will out perform the wood design in all performance specifications. Moreover, the resiliency, elasticity, flexibility, and ability to be impervious to weathering elements, extend longtivity, and require little or no maintenance are important features of the present invention.
A preferred embodiment to the spacer block of the instant invention is a generally rectangular block or cube including corded-out cavities to reduce weight and one or more tabs on the top and/or sides projecting outwardly for cooperatively engaging the sides and top edge of the post. A preferred embodiment is approximately 4 inches in width which is the same as conventional I-beam posts providing a lightweight, compact, high strength spacer block as compared to conventional spacer blocks made from wood or plastic typically having a width of 6 inches or more. A tab projecting outward from the face of the spacer block provides a support member to hold, steady, and even align the guard rail which rests thereon providing a means for one individual to mount the guard rail on spacer blocks, whereas conventional spacer blocks do not support the guard rail prior to attachment thereto and require at least two individuals if not three to attach the guard rail to the spacer block and post.
The preferred embodiment of the spacer block of the present invention comprises one or more polymers, such as (polyethylene, polypropylene, polyethylene terephthalate, nylon, polyurethane, polyvinyl chloride, and mixtures thereof), and preferably a polymer/rubber blend. Other plastic materials which may be used may be selected from ABS, Acetyl, polypropylene oxide, nylon PBT, polycarbonate, polystyrene, modified polyphenylene oxide, polyester, fiberglass filled nylon, fiberglass filled styrene, fiberglass filled SAN, acrylic, ethylene copolymers, ionomers, and polysulfone. Of course the spacer block of the present invention may be formed of a single type of polymer or mixtures of various polymers. The polymers may be virgin material or the spacer block may be composed of at least some if not all of regrind materials, such as reground polyethylene, ethylene. The rubber and/or elastomeric compound which can be incorporated in the formulation may be comprised of a natural rubber or synthetic rubber, either virgin, regrind material or combinations thereof. It is contemplated that fiberglass may also be used as an additive or substitute raw material for all or at least a portion of the plastic material. Fillers such as wood chips. sawdust, calcium carbonate may also be used. The rubber from used tires have been a huge problem for the environment and could be utilized as the source of rubber for the instant invention. Moreover, the spacer blocks may themselves be recyclable.
One preferred embodiment of the present invention is a spacer block utilizing a blend of at least one polymer including one or more of the plastic materials set forth heretofore, together with at least one rubber or elastomeric materials mixed and molded together with the polymer(s). The ability to mold large blocks of plastic containing virgin, and/or regrind thermoplastics which can be obtained from reusable containers, alone or together with virgin or grind rubber from used tires or other sources providing a useful means of disposal and recycling of waste products. One preferred embodiment of the invention utilizes grind rubber in combination with a one or more thermoplastics extruded or molded by low pressure injection molding or vacuum forming. The molding process is believed to encapsulate the rubber particles with the thermoplastic melt thereby providing a stronger blended product with enhanced performance capabilities as compared to a simple mixture of thermoplastic and rubber particles compressed together under high pressure. One source of the grind rubber is reground vehicle tires, representing a new method of disposal of used tires.
Another important aspect of the present invention, is the molding of the spacer blocks using a structural foam process to further increase strength, reduce costs, and reduce the weight of the spacer blocks. The structural foam techniques utilizes a gas and/or chemical foaming agent injection process in the molding operation to form a foam core creating structural support webbing between solid plastic skins to increase structural strength and reduce weight and cost. The design of the block to include structural external webbing between void spaces in the spacer blocks of the instant invention further provides strength and weight advantages to the space block. The use of the blend of plastics and rubber and/or the webbing within the block cavity are unique features; however, in addition the utilization of structural foam forming the skin provides another novel feature not utilized in spacer blocks taught in the prior art.
These embodiments of the present invention can be utilized with a spacer block molded having solid walls as well as a spacer block molded by structural foam whereby the walls are composed of an inner and outer skin with webbing thereinbetween.
It is contemplated that all or at least a portion of the spacer block 10 could be filled with foam, gel, finely ground solid material, or even a liquid such as water and/or alcohol and water such as a glycol to inhibit freezing, or that the cavity could contain a bag containing same to cushion and absorb impact thereto. The material could be contained within the spacer block body or insertion of a container into the webbing or cavity formed within the spacer block could even be removable, such as a water bag or a deformable plastic container such as a jug. Moreover, a cellular core could be utilized for impact absorption within the cavities, or an impact absorbing block filled with cellular material, a gel, or a liquid could be disposed within the cavities formed in the present spacer blocks.
Conventional spacer block assemblies require one person to hold the wood block while another holds the guardrail section and a third person installs the bolt, which holds the entire assembly together. The instant invention includes a hanger enabling the spacer block to hang on the I beam by itself. On the bottom of the spacer block is a guard rail resting tab so that the guard rail can be lifted and placed on the resting tab for mounting to the spacer block and post.
One person can install a section by placing the bolt with in hands reach, it is possible for one person to lift a section of guardrail and rest it on the rail tab and install the bolt. A section of guardrail can be installed by a single person at a much faster pace than the designs of today. Therefor, it is an objective of the present invention to provide a spacer block which enables one person to mount a guard rail to a spacer block and post.
It is another objective of the present invention to provide a spacer block which is splinter-less, has a longer life span than wood, lighter than wood.
It is an object of the present invention to provide a plastic/rubber composite block which meets all required specifications set forth by the Federal Highway Administration.
It is an object of the present invention to provide a spacer block which is environmentally friendly and be capable of being manufactured using recycled plastic, tires, and/or combinations thereof.
It is an object of the present invention to provide a plastic/rubber composition which will out-last the wood blocks of today.
It is an object of the present invention to provide a plastic-rubber composite spacer block that will meet or exceed the requirements of today""s wooden block.
Another important optional feature is the utilization of a plastic/rubber copolymer material to enhance the performance of the spacer block.
Yet another object of the present invention is to provide an embodiment which may be formed from structural foam in order to optimize the weight to strength of the spacer block.
Other objects, features, and advantages of the invention will be apparent with the following detailed description taken in conjunction with the accompanying drawings showing a preferred embodiment of the invention.